Browse code

encoder for adobe's flash ScreenVideo2 codec

Joshua Warner authored on 2011/04/29 09:25:56
Showing 6 changed files
... ...
@@ -342,6 +342,7 @@ version 0.5:
342 342
 - Gopher client support
343 343
 - MXF D-10 muxer
344 344
 - generic metadata API
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+- flash ScreenVideo2 encoder
345 346
 
346 347
 
347 348
 version 0.4.9-pre1:
... ...
@@ -1275,6 +1275,7 @@ flac_decoder_select="golomb"
1275 1275
 flac_encoder_select="golomb lpc"
1276 1276
 flashsv_decoder_select="zlib"
1277 1277
 flashsv_encoder_select="zlib"
1278
+flashsv2_encoder_select="zlib"
1278 1279
 flv_decoder_select="h263_decoder"
1279 1280
 flv_encoder_select="h263_encoder"
1280 1281
 fraps_decoder_select="huffman"
... ...
@@ -401,6 +401,7 @@ following image formats are supported:
401 401
     @tab experimental lossless codec (fourcc: FFV1)
402 402
 @item Flash Screen Video v1  @tab  X  @tab  X
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     @tab fourcc: FSV1
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+@item Flash Screen Video v2  @tab  X
404 405
 @item Flash Video (FLV)      @tab  X  @tab  X
405 406
     @tab Sorenson H.263 used in Flash
406 407
 @item Fraps                  @tab     @tab  X
... ...
@@ -145,6 +145,7 @@ OBJS-$(CONFIG_FLAC_DECODER)            += flacdec.o flacdata.o flac.o vorbis_dat
145 145
 OBJS-$(CONFIG_FLAC_ENCODER)            += flacenc.o flacdata.o flac.o
146 146
 OBJS-$(CONFIG_FLASHSV_DECODER)         += flashsv.o
147 147
 OBJS-$(CONFIG_FLASHSV_ENCODER)         += flashsvenc.o
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+OBJS-$(CONFIG_FLASHSV2_ENCODER)        += flashsv2enc.o
148 149
 OBJS-$(CONFIG_FLIC_DECODER)            += flicvideo.o
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 OBJS-$(CONFIG_FOURXM_DECODER)          += 4xm.o
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 OBJS-$(CONFIG_FRAPS_DECODER)           += fraps.o
... ...
@@ -108,6 +108,7 @@ void avcodec_register_all(void)
108 108
     REGISTER_ENCDEC  (FFV1, ffv1);
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     REGISTER_ENCDEC  (FFVHUFF, ffvhuff);
110 110
     REGISTER_ENCDEC  (FLASHSV, flashsv);
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+    REGISTER_ENCODER (FLASHSV2, flashsv2);
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     REGISTER_DECODER (FLIC, flic);
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     REGISTER_ENCDEC  (FLV, flv);
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     REGISTER_DECODER (FOURXM, fourxm);
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new file mode 100644
... ...
@@ -0,0 +1,913 @@
0
+/*
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+ * Flash Screen Video Version 2 encoder
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+ * Copyright (C) 2009 Joshua Warner
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+ *
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+ * This file is part of FFmpeg.
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+ *
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+ * FFmpeg is free software; you can redistribute it and/or
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+ * modify it under the terms of the GNU Lesser General Public
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+ * License as published by the Free Software Foundation; either
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+ * version 2.1 of the License, or (at your option) any later version.
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+ *
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+ * FFmpeg is distributed in the hope that it will be useful,
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+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
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+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14
+ * Lesser General Public License for more details.
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+ *
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+ * You should have received a copy of the GNU Lesser General Public
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+ * License along with FFmpeg; if not, write to the Free Software
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+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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+ */
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+
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+/**
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+ * @file libavcodec/flashsv2enc.c
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+ * Flash Screen Video Version 2 encoder
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+ * @author Joshua Warner
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+ */
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+
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+/* Differences from version 1 stream:
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+ * NOTE: Currently, the only player that supports version 2 streams is Adobe Flash Player itself.
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+ * * Supports sending only a range of scanlines in a block,
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+ *   indicating a difference from the corresponding block in the last keyframe.
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+ * * Supports initializing the zlib dictionary with data from the corresponding
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+ *   block in the last keyframe, to improve compression.
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+ * * Supports a hybrid 15-bit rgb / 7-bit palette color space.
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+ */
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+
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+/* TODO:
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+ * Don't keep Block structures for both current frame and keyframe.
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+ * Make better heuristics for deciding stream parameters (optimum_* functions).  Currently these return constants.
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+ * Figure out how to encode palette information in the stream, choose an optimum palette at each keyframe.
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+ * Figure out how the zlibPrimeCompressCurrent flag works, implement support.
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+ * Find other sample files (that weren't generated here), develop a decoder.
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+ */
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+
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+#include <stdio.h>
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+#include <stdlib.h>
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+#include <zlib.h>
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+
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+#include "libavutil/imgutils.h"
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+#include "avcodec.h"
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+#include "put_bits.h"
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+#include "bytestream.h"
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+
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+#define HAS_IFRAME_IMAGE 0x02
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+#define HAS_PALLET_INFO 0x01
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+
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+#define COLORSPACE_BGR 0x00
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+#define COLORSPACE_15_7 0x10
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+#define HAS_DIFF_BLOCKS 0x04
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+#define ZLIB_PRIME_COMPRESS_CURRENT 0x02
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+#define ZLIB_PRIME_COMPRESS_PREVIOUS 0x01
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+
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+// Disables experimental "smart" parameter-choosing code, as well as the statistics that it depends on.
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+// At the moment, the "smart" code is a great example of how the parameters *shouldn't* be chosen.
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+#define FLASHSV2_DUMB
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+
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+typedef struct Block {
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+    uint8_t *enc;
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+    uint8_t *sl_begin, *sl_end;
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+    int enc_size;
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+    uint8_t *data;
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+    unsigned long data_size;
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+
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+    uint8_t start, len;
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+    uint8_t dirty;
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+    uint8_t col, row, width, height;
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+    uint8_t flags;
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+} Block;
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+
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+typedef struct Palette {
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+    unsigned colors[128];
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+    uint8_t index[1 << 15];
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+} Palette;
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+
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+typedef struct FlashSV2Context {
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+    AVCodecContext *avctx;
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+    uint8_t *current_frame;
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+    uint8_t *key_frame;
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+    AVFrame frame;
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+    uint8_t *encbuffer;
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+    uint8_t *keybuffer;
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+    uint8_t *databuffer;
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+
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+    Block *frame_blocks;
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+    Block *key_blocks;
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+    int frame_size;
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+    int blocks_size;
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+
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+    int use15_7, dist, comp;
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+
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+    int rows, cols;
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+
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+    int last_key_frame;
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+
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+    int image_width, image_height;
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+    int block_width, block_height;
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+    uint8_t flags;
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+    uint8_t use_custom_palette;
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+    uint8_t palette_type;       ///< 0=>default, 1=>custom - changed when palette regenerated.
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+    Palette palette;
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+#ifndef FLASHSV2_DUMB
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+    double tot_blocks;          ///< blocks encoded since last keyframe
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+    double diff_blocks;         ///< blocks that were different since last keyframe
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+    double tot_lines;           ///< total scanlines in image since last keyframe
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+    double diff_lines;          ///< scanlines that were different since last keyframe
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+    double raw_size;            ///< size of raw frames since last keyframe
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+    double comp_size;           ///< size of compressed data since last keyframe
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+    double uncomp_size;         ///< size of uncompressed data since last keyframe
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+
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+    double total_bits;          ///< total bits written to stream so far
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+#endif
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+} FlashSV2Context;
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+
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+static av_cold void cleanup(FlashSV2Context * s)
124
+{
125
+    if (s->encbuffer)
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+        av_free(s->encbuffer);
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+    if (s->keybuffer)
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+        av_free(s->keybuffer);
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+    if (s->databuffer)
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+        av_free(s->databuffer);
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+    if (s->current_frame)
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+        av_free(s->current_frame);
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+    if (s->key_frame)
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+        av_free(s->key_frame);
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+
136
+    if (s->frame_blocks)
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+        av_free(s->frame_blocks);
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+    if (s->key_blocks)
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+        av_free(s->key_blocks);
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+}
141
+
142
+static void init_blocks(FlashSV2Context * s, Block * blocks,
143
+                        uint8_t * encbuf, uint8_t * databuf)
144
+{
145
+    int row, col;
146
+    Block *b;
147
+    for (col = 0; col < s->cols; col++) {
148
+        for (row = 0; row < s->rows; row++) {
149
+            b = blocks + (col + row * s->cols);
150
+            b->width = (col < s->cols - 1) ?
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+                s->block_width :
152
+                s->image_width - col * s->block_width;
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+
154
+            b->height = (row < s->rows - 1) ?
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+                s->block_height :
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+                s->image_height - row * s->block_height;
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+
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+            b->row   = row;
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+            b->col   = col;
160
+            b->enc   = encbuf;
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+            b->data  = databuf;
162
+            encbuf  += b->width * b->height * 3;
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+            databuf += !databuf ? 0 : b->width * b->height * 6;
164
+        }
165
+    }
166
+}
167
+
168
+static void reset_stats(FlashSV2Context * s)
169
+{
170
+#ifndef FLASHSV2_DUMB
171
+    s->diff_blocks = 0.1;
172
+    s->tot_blocks = 1;
173
+    s->diff_lines = 0.1;
174
+    s->tot_lines = 1;
175
+    s->raw_size = s->comp_size = s->uncomp_size = 10;
176
+#endif
177
+}
178
+
179
+static av_cold int flashsv2_encode_init(AVCodecContext * avctx)
180
+{
181
+    FlashSV2Context *s = avctx->priv_data;
182
+
183
+    s->avctx = avctx;
184
+
185
+    s->comp = avctx->compression_level;
186
+    if (s->comp == -1)
187
+        s->comp = 9;
188
+    if (s->comp < 0 || s->comp > 9) {
189
+        av_log(avctx, AV_LOG_ERROR,
190
+               "Compression level should be 0-9, not %d\n", s->comp);
191
+        return -1;
192
+    }
193
+
194
+
195
+    if ((avctx->width > 4095) || (avctx->height > 4095)) {
196
+        av_log(avctx, AV_LOG_ERROR,
197
+               "Input dimensions too large, input must be max 4096x4096 !\n");
198
+        return -1;
199
+    }
200
+
201
+    if (av_image_check_size(avctx->width, avctx->height, 0, avctx) < 0)
202
+        return -1;
203
+
204
+
205
+    s->last_key_frame = 0;
206
+
207
+    s->image_width  = avctx->width;
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+    s->image_height = avctx->height;
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+
210
+    s->block_width  = (s->image_width /  12) & ~15;
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+    s->block_height = (s->image_height / 12) & ~15;
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+
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+    s->rows = (s->image_height + s->block_height - 1) / s->block_height;
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+    s->cols = (s->image_width +  s->block_width -  1) / s->block_width;
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+
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+    s->frame_size  = s->image_width * s->image_height * 3;
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+    s->blocks_size = s->rows * s->cols * sizeof(Block);
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+
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+    s->encbuffer     = av_mallocz(s->frame_size);
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+    s->keybuffer     = av_mallocz(s->frame_size);
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+    s->databuffer    = av_mallocz(s->frame_size * 6);
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+    s->current_frame = av_mallocz(s->frame_size);
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+    s->key_frame     = av_mallocz(s->frame_size);
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+    s->frame_blocks  = av_mallocz(s->blocks_size);
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+    s->key_blocks    = av_mallocz(s->blocks_size);
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+
227
+    init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);
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+    init_blocks(s, s->key_blocks,   s->keybuffer, 0);
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+    reset_stats(s);
230
+#ifndef FLASHSV2_DUMB
231
+    s->total_bits = 1;
232
+#endif
233
+
234
+    s->use_custom_palette =  0;
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+    s->palette_type       = -1;        // so that the palette will be generated in reconfigure_at_keyframe
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+
237
+    if (!s->encbuffer || !s->keybuffer || !s->databuffer
238
+        || !s->current_frame || !s->key_frame || !s->key_blocks
239
+        || !s->frame_blocks) {
240
+        av_log(avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
241
+        cleanup(s);
242
+        return -1;
243
+    }
244
+
245
+    return 0;
246
+}
247
+
248
+static int new_key_frame(FlashSV2Context * s)
249
+{
250
+    int i;
251
+    FFSWAP(uint8_t * , s->keybuffer, s->encbuffer);
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+    memcpy(s->key_blocks, s->frame_blocks, s->blocks_size);
253
+    memcpy(s->key_frame, s->current_frame, s->frame_size);
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+
255
+    for (i = 0; i < s->rows * s->cols; i++) {
256
+        s->key_blocks[i].enc += (s->keybuffer - s->encbuffer);
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+        s->key_blocks[i].sl_begin = 0;
258
+        s->key_blocks[i].sl_end   = 0;
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+        s->key_blocks[i].data     = 0;
260
+    }
261
+
262
+    return 0;
263
+}
264
+
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+static int write_palette(FlashSV2Context * s, uint8_t * buf, int buf_size)
266
+{
267
+    //this isn't implemented yet!  Default palette only!
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+    return -1;
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+}
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+
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+static int write_header(FlashSV2Context * s, uint8_t * buf, int buf_size)
272
+{
273
+    PutBitContext pb;
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+    int buf_pos, len;
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+
276
+    if (buf_size < 5)
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+        return -1;
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+
279
+    init_put_bits(&pb, buf, buf_size * 8);
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+
281
+    put_bits(&pb, 4, (s->block_width  >> 4) - 1);
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+    put_bits(&pb, 12, s->image_width);
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+    put_bits(&pb, 4, (s->block_height >> 4) - 1);
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+    put_bits(&pb, 12, s->image_height);
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+
286
+    flush_put_bits(&pb);
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+    buf_pos = 4;
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+
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+    buf[buf_pos++] = s->flags;
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+
291
+    if (s->flags & HAS_PALLET_INFO) {
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+        len = write_palette(s, buf + buf_pos, buf_size - buf_pos);
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+        if (len < 0)
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+            return -1;
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+        buf_pos += len;
296
+    }
297
+
298
+    return buf_pos;
299
+}
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+
301
+static int write_block(Block * b, uint8_t * buf, int buf_size)
302
+{
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+    int buf_pos = 0;
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+    unsigned block_size = b->data_size;
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+
306
+    if (b->flags & HAS_DIFF_BLOCKS)
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+        block_size += 2;
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+    if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT)
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+        block_size += 2;
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+    if (block_size > 0)
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+        block_size += 1;
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+    if (buf_size < block_size + 2)
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+        return -1;
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+
315
+    buf[buf_pos++] = block_size >> 8;
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+    buf[buf_pos++] = block_size;
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+
318
+    if (block_size == 0)
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+        return buf_pos;
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+
321
+    buf[buf_pos++] = b->flags;
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+
323
+    if (b->flags & HAS_DIFF_BLOCKS) {
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+        buf[buf_pos++] = (uint8_t) (b->start);
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+        buf[buf_pos++] = (uint8_t) (b->len);
326
+    }
327
+
328
+    if (b->flags & ZLIB_PRIME_COMPRESS_CURRENT) {
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+        //This feature of the format is poorly understood, and as of now, unused.
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+        buf[buf_pos++] = (uint8_t) (b->col);
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+        buf[buf_pos++] = (uint8_t) (b->row);
332
+    }
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+
334
+    memcpy(buf + buf_pos, b->data, b->data_size);
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+
336
+    buf_pos += b->data_size;
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+
338
+    return buf_pos;
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+}
340
+
341
+static int encode_zlib(Block * b, uint8_t * buf, unsigned long *buf_size, int comp)
342
+{
343
+    int res = compress2(buf, buf_size, b->sl_begin, b->sl_end - b->sl_begin, comp);
344
+    return res == Z_OK ? 0 : -1;
345
+}
346
+
347
+static int encode_zlibprime(Block * b, Block * prime, uint8_t * buf,
348
+                            int *buf_size, int comp)
349
+{
350
+    z_stream s;
351
+    int res;
352
+    s.zalloc = NULL;
353
+    s.zfree  = NULL;
354
+    s.opaque = NULL;
355
+    res = deflateInit(&s, comp);
356
+    if (res < 0)
357
+        return -1;
358
+
359
+    s.next_in  = prime->enc;
360
+    s.avail_in = prime->enc_size;
361
+    while (s.avail_in > 0) {
362
+        s.next_out  = buf;
363
+        s.avail_out = *buf_size;
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+        res = deflate(&s, Z_SYNC_FLUSH);
365
+        if (res < 0)
366
+            return -1;
367
+    }
368
+
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+    s.next_in   = b->sl_begin;
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+    s.avail_in  = b->sl_end - b->sl_begin;
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+    s.next_out  = buf;
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+    s.avail_out = *buf_size;
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+    res = deflate(&s, Z_FINISH);
374
+    deflateEnd(&s);
375
+    *buf_size -= s.avail_out;
376
+    if (res != Z_STREAM_END)
377
+        return -1;
378
+    return 0;
379
+}
380
+
381
+static int encode_bgr(Block * b, const uint8_t * src, int stride)
382
+{
383
+    int i;
384
+    uint8_t *ptr = b->enc;
385
+    for (i = 0; i < b->start; i++)
386
+        memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
387
+    b->sl_begin = ptr + i * b->width * 3;
388
+    for (; i < b->start + b->len; i++)
389
+        memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
390
+    b->sl_end = ptr + i * b->width * 3;
391
+    for (; i < b->height; i++)
392
+        memcpy(ptr + i * b->width * 3, src + i * stride, b->width * 3);
393
+    b->enc_size = ptr + i * b->width * 3 - b->enc;
394
+    return b->enc_size;
395
+}
396
+
397
+static inline unsigned pixel_color15(const uint8_t * src)
398
+{
399
+    return (src[0] >> 3) | ((src[1] & 0xf8) << 2) | ((src[2] & 0xf8) << 7);
400
+}
401
+
402
+static inline unsigned int chroma_diff(unsigned int c1, unsigned int c2)
403
+{
404
+    unsigned int t1 = (c1 & 0x000000ff) + ((c1 & 0x0000ff00) >> 8) + ((c1 & 0x00ff0000) >> 16);
405
+    unsigned int t2 = (c2 & 0x000000ff) + ((c2 & 0x0000ff00) >> 8) + ((c2 & 0x00ff0000) >> 16);
406
+
407
+    return abs(t1 - t2) + abs((c1 & 0x000000ff) - (c2 & 0x000000ff)) +
408
+        abs(((c1 & 0x0000ff00) >> 8) - ((c2 & 0x0000ff00) >> 8)) +
409
+        abs(((c1 & 0x00ff0000) >> 16) - ((c2 & 0x00ff0000) >> 16));
410
+}
411
+
412
+static inline int pixel_color7_fast(Palette * palette, unsigned c15)
413
+{
414
+    return palette->index[c15];
415
+}
416
+
417
+static int pixel_color7_slow(Palette * palette, unsigned color)
418
+{
419
+    int i, min = 0x7fffffff;
420
+    int minc = -1;
421
+    for (i = 0; i < 128; i++) {
422
+        int c1 = palette->colors[i];
423
+        int diff = chroma_diff(c1, color);
424
+        if (diff < min) {
425
+            min = diff;
426
+            minc = i;
427
+        }
428
+    }
429
+    return minc;
430
+}
431
+
432
+static inline unsigned pixel_bgr(const uint8_t * src)
433
+{
434
+    return (src[0]) | (src[1] << 8) | (src[2] << 16);
435
+}
436
+
437
+static int write_pixel_15_7(Palette * palette, uint8_t * dest, const uint8_t * src,
438
+                            int dist)
439
+{
440
+    unsigned c15 = pixel_color15(src);
441
+    unsigned color = pixel_bgr(src);
442
+    int d15 = chroma_diff(color, color & 0x00f8f8f8);
443
+    int c7 = pixel_color7_fast(palette, c15);
444
+    int d7 = chroma_diff(color, palette->colors[c7]);
445
+    if (dist + d15 >= d7) {
446
+        dest[0] = (uint8_t) c7;
447
+        return 1;
448
+    } else {
449
+        dest[0] = 0x80 | (uint8_t) (c15 >> 8);
450
+        dest[1] = c15 & 0xff;
451
+        return 2;
452
+    }
453
+}
454
+
455
+static int update_palette_index(Palette * palette)
456
+{
457
+    int r, g, b;
458
+    unsigned int bgr, c15, index;
459
+    for (r = 4; r < 256; r += 8) {
460
+        for (g = 4; g < 256; g += 8) {
461
+            for (b = 4; b < 256; b += 8) {
462
+                bgr = b | (g << 8) | (r << 16);
463
+                c15 = (b >> 3) | ((g & 0xf8) << 2) | ((r & 0xf8) << 7);
464
+                index = pixel_color7_slow(palette, bgr);
465
+
466
+                palette->index[c15] = index;
467
+            }
468
+        }
469
+    }
470
+    return 0;
471
+}
472
+
473
+static const unsigned int default_screen_video_v2_palette[128] = {
474
+    0x00000000, 0x00333333, 0x00666666, 0x00999999, 0x00CCCCCC, 0x00FFFFFF,
475
+    0x00330000, 0x00660000, 0x00990000, 0x00CC0000, 0x00FF0000, 0x00003300,
476
+    0x00006600, 0x00009900, 0x0000CC00, 0x0000FF00, 0x00000033, 0x00000066,
477
+    0x00000099, 0x000000CC, 0x000000FF, 0x00333300, 0x00666600, 0x00999900,
478
+    0x00CCCC00, 0x00FFFF00, 0x00003333, 0x00006666, 0x00009999, 0x0000CCCC,
479
+    0x0000FFFF, 0x00330033, 0x00660066, 0x00990099, 0x00CC00CC, 0x00FF00FF,
480
+    0x00FFFF33, 0x00FFFF66, 0x00FFFF99, 0x00FFFFCC, 0x00FF33FF, 0x00FF66FF,
481
+    0x00FF99FF, 0x00FFCCFF, 0x0033FFFF, 0x0066FFFF, 0x0099FFFF, 0x00CCFFFF,
482
+    0x00CCCC33, 0x00CCCC66, 0x00CCCC99, 0x00CCCCFF, 0x00CC33CC, 0x00CC66CC,
483
+    0x00CC99CC, 0x00CCFFCC, 0x0033CCCC, 0x0066CCCC, 0x0099CCCC, 0x00FFCCCC,
484
+    0x00999933, 0x00999966, 0x009999CC, 0x009999FF, 0x00993399, 0x00996699,
485
+    0x0099CC99, 0x0099FF99, 0x00339999, 0x00669999, 0x00CC9999, 0x00FF9999,
486
+    0x00666633, 0x00666699, 0x006666CC, 0x006666FF, 0x00663366, 0x00669966,
487
+    0x0066CC66, 0x0066FF66, 0x00336666, 0x00996666, 0x00CC6666, 0x00FF6666,
488
+    0x00333366, 0x00333399, 0x003333CC, 0x003333FF, 0x00336633, 0x00339933,
489
+    0x0033CC33, 0x0033FF33, 0x00663333, 0x00993333, 0x00CC3333, 0x00FF3333,
490
+    0x00003366, 0x00336600, 0x00660033, 0x00006633, 0x00330066, 0x00663300,
491
+    0x00336699, 0x00669933, 0x00993366, 0x00339966, 0x00663399, 0x00996633,
492
+    0x006699CC, 0x0099CC66, 0x00CC6699, 0x0066CC99, 0x009966CC, 0x00CC9966,
493
+    0x0099CCFF, 0x00CCFF99, 0x00FF99CC, 0x0099FFCC, 0x00CC99FF, 0x00FFCC99,
494
+    0x00111111, 0x00222222, 0x00444444, 0x00555555, 0x00AAAAAA, 0x00BBBBBB,
495
+    0x00DDDDDD, 0x00EEEEEE
496
+};
497
+
498
+static int generate_default_palette(Palette * palette)
499
+{
500
+    memcpy(palette->colors, default_screen_video_v2_palette,
501
+           sizeof(default_screen_video_v2_palette));
502
+
503
+    return update_palette_index(palette);
504
+}
505
+
506
+static int generate_optimum_palette(Palette * palette, const uint8_t * image,
507
+                                   int width, int height, int stride)
508
+{
509
+    //this isn't implemented yet!  Default palette only!
510
+    return -1;
511
+}
512
+
513
+static inline int encode_15_7_sl(Palette * palette, uint8_t * dest,
514
+                                 const uint8_t * src, int width, int dist)
515
+{
516
+    int len = 0, x;
517
+    for (x = 0; x < width; x++) {
518
+        len += write_pixel_15_7(palette, dest + len, src + 3 * x, dist);
519
+    }
520
+    return len;
521
+}
522
+
523
+static int encode_15_7(Palette * palette, Block * b, const uint8_t * src,
524
+                       int stride, int dist)
525
+{
526
+    int i;
527
+    uint8_t *ptr = b->enc;
528
+    for (i = 0; i < b->start; i++)
529
+        ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
530
+    b->sl_begin = ptr;
531
+    for (; i < b->start + b->len; i++)
532
+        ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
533
+    b->sl_end = ptr;
534
+    for (; i < b->height; i++)
535
+        ptr += encode_15_7_sl(palette, ptr, src + i * stride, b->width, dist);
536
+    b->enc_size = ptr - b->enc;
537
+    return b->enc_size;
538
+}
539
+
540
+static int encode_block(Palette * palette, Block * b, Block * prev,
541
+                        const uint8_t * src, int stride, int comp, int dist,
542
+                        int keyframe)
543
+{
544
+    unsigned buf_size = b->width * b->height * 6;
545
+    uint8_t buf[buf_size];
546
+    int res;
547
+    if (b->flags & COLORSPACE_15_7) {
548
+        encode_15_7(palette, b, src, stride, dist);
549
+    } else {
550
+        encode_bgr(b, src, stride);
551
+    }
552
+
553
+    if (b->len > 0) {
554
+        b->data_size = buf_size;
555
+        res = encode_zlib(b, b->data, &b->data_size, comp);
556
+        if (res)
557
+            return res;
558
+
559
+        if (!keyframe) {
560
+            res = encode_zlibprime(b, prev, buf, &buf_size, comp);
561
+            if (res)
562
+                return res;
563
+
564
+            if (buf_size < b->data_size) {
565
+                b->data_size = buf_size;
566
+                memcpy(b->data, buf, buf_size);
567
+                b->flags |= ZLIB_PRIME_COMPRESS_PREVIOUS;
568
+            }
569
+        }
570
+    } else {
571
+        b->data_size = 0;
572
+    }
573
+    return 0;
574
+}
575
+
576
+static int compare_sl(FlashSV2Context * s, Block * b, const uint8_t * src,
577
+                      uint8_t * frame, uint8_t * key, int y, int keyframe)
578
+{
579
+    if (memcmp(src, frame, b->width * 3) != 0) {
580
+        b->dirty = 1;
581
+        memcpy(frame, src, b->width * 3);
582
+#ifndef FLASHSV2_DUMB
583
+        s->diff_lines++;
584
+#endif
585
+    }
586
+    if (memcmp(src, key, b->width * 3) != 0) {
587
+        if (b->len == 0)
588
+            b->start = y;
589
+        b->len = y + 1 - b->start;
590
+    }
591
+    return 0;
592
+}
593
+
594
+static int mark_all_blocks(FlashSV2Context * s, const uint8_t * src, int stride,
595
+                           int keyframe)
596
+{
597
+    int sl, rsl, col, pos, possl;
598
+    Block *b;
599
+    for (sl = s->image_height - 1; sl >= 0; sl--) {
600
+        for (col = 0; col < s->cols; col++) {
601
+            rsl = s->image_height - sl - 1;
602
+            b = s->frame_blocks + col + rsl / s->block_height * s->cols;
603
+            possl = stride * sl + col * s->block_width * 3;
604
+            pos = s->image_width * rsl * 3 + col * s->block_width * 3;
605
+            compare_sl(s, b, src + possl, s->current_frame + pos,
606
+                       s->key_frame + pos, rsl % s->block_height, keyframe);
607
+        }
608
+    }
609
+#ifndef FLASHSV2_DUMB
610
+    s->tot_lines += s->image_height * s->cols;
611
+#endif
612
+    return 0;
613
+}
614
+
615
+static int encode_all_blocks(FlashSV2Context * s, int keyframe)
616
+{
617
+    int row, col, res;
618
+    uint8_t *data;
619
+    Block *b, *prev;
620
+    for (row = 0; row < s->rows; row++) {
621
+        for (col = 0; col < s->cols; col++) {
622
+            b = s->frame_blocks + (row * s->cols + col);
623
+            prev = s->key_blocks + (row * s->cols + col);
624
+            if (keyframe) {
625
+                b->start = 0;
626
+                b->len = b->height;
627
+                b->flags = s->use15_7 ? COLORSPACE_15_7 : 0;
628
+            } else if (!b->dirty) {
629
+                b->start = 0;
630
+                b->len = 0;
631
+                b->data_size = 0;
632
+                b->flags = s->use15_7 ? COLORSPACE_15_7 : 0;
633
+                continue;
634
+            } else {
635
+                b->flags = s->use15_7 ? COLORSPACE_15_7 | HAS_DIFF_BLOCKS : HAS_DIFF_BLOCKS;
636
+            }
637
+            data = s->current_frame + s->image_width * 3 * s->block_height * row + s->block_width * col * 3;
638
+            res = encode_block(&s->palette, b, prev, data, s->image_width * 3, s->comp, s->dist, keyframe);
639
+#ifndef FLASHSV2_DUMB
640
+            if (b->dirty)
641
+                s->diff_blocks++;
642
+            s->comp_size += b->data_size;
643
+            s->uncomp_size += b->enc_size;
644
+#endif
645
+            if (res)
646
+                return res;
647
+        }
648
+    }
649
+#ifndef FLASHSV2_DUMB
650
+    s->raw_size += s->image_width * s->image_height * 3;
651
+    s->tot_blocks += s->rows * s->cols;
652
+#endif
653
+    return 0;
654
+}
655
+
656
+static int write_all_blocks(FlashSV2Context * s, uint8_t * buf,
657
+                            int buf_size)
658
+{
659
+    int row, col, buf_pos = 0, len;
660
+    Block *b;
661
+    for (row = 0; row < s->rows; row++) {
662
+        for (col = 0; col < s->cols; col++) {
663
+            b = s->frame_blocks + row * s->cols + col;
664
+            len = write_block(b, buf + buf_pos, buf_size - buf_pos);
665
+            b->start = b->len = b->dirty = 0;
666
+            if (len < 0)
667
+                return len;
668
+            buf_pos += len;
669
+        }
670
+    }
671
+    return buf_pos;
672
+}
673
+
674
+static int write_bitstream(FlashSV2Context * s, const uint8_t * src, int stride,
675
+                           uint8_t * buf, int buf_size, int keyframe)
676
+{
677
+    int buf_pos, res;
678
+
679
+    res = mark_all_blocks(s, src, stride, keyframe);
680
+    if (res)
681
+        return res;
682
+    res = encode_all_blocks(s, keyframe);
683
+    if (res)
684
+        return res;
685
+
686
+    res = write_header(s, buf, buf_size);
687
+    if (res < 0) {
688
+        return res;
689
+    } else {
690
+        buf_pos = res;
691
+    }
692
+    res = write_all_blocks(s, buf + buf_pos, buf_size - buf_pos);
693
+    if (res < 0)
694
+        return res;
695
+    buf_pos += res;
696
+#ifndef FLASHSV2_DUMB
697
+    s->total_bits += ((double) buf_pos) * 8.0;
698
+#endif
699
+
700
+    return buf_pos;
701
+}
702
+
703
+static void recommend_keyframe(FlashSV2Context * s, int *keyframe)
704
+{
705
+#ifndef FLASHSV2_DUMB
706
+    double block_ratio, line_ratio, enc_ratio, comp_ratio, data_ratio;
707
+    if (s->avctx->gop_size > 0) {
708
+        block_ratio = s->diff_blocks / s->tot_blocks;
709
+        line_ratio = s->diff_lines / s->tot_lines;
710
+        enc_ratio = s->uncomp_size / s->raw_size;
711
+        comp_ratio = s->comp_size / s->uncomp_size;
712
+        data_ratio = s->comp_size / s->raw_size;
713
+
714
+        if ((block_ratio >= 0.5 && line_ratio / block_ratio <= 0.5) || line_ratio >= 0.95) {
715
+            *keyframe = 1;
716
+            return;
717
+        }
718
+    }
719
+#else
720
+    return;
721
+#endif
722
+}
723
+
724
+static const double block_size_fraction = 1.0 / 300;
725
+static int optimum_block_width(FlashSV2Context * s)
726
+{
727
+#ifndef FLASHSV2_DUMB
728
+    double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;
729
+    double width = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_width;
730
+    int pwidth = ((int) width);
731
+    return FFCLIP(pwidth & ~15, 256, 16);
732
+#else
733
+    return 64;
734
+#endif
735
+}
736
+
737
+static int optimum_block_height(FlashSV2Context * s)
738
+{
739
+#ifndef FLASHSV2_DUMB
740
+    double save = (1-pow(s->diff_lines/s->diff_blocks/s->block_height, 0.5)) * s->comp_size/s->tot_blocks;
741
+    double height = block_size_fraction * sqrt(0.5 * save * s->rows * s->cols) * s->image_height;
742
+    int pheight = ((int) height);
743
+    return FFCLIP(pheight & ~15, 256, 16);
744
+#else
745
+    return 64;
746
+#endif
747
+}
748
+
749
+static const double use15_7_threshold = 8192;
750
+
751
+static int optimum_use15_7(FlashSV2Context * s)
752
+{
753
+#ifndef FLASHSV2_DUMB
754
+    double ideal = ((double)(s->avctx->bit_rate * s->avctx->time_base.den * s->avctx->ticks_per_frame)) /
755
+        ((double) s->avctx->time_base.num) * s->avctx->frame_number;
756
+    if (ideal + use15_7_threshold < s->total_bits) {
757
+        return 1;
758
+    } else {
759
+        return 0;
760
+    }
761
+#else
762
+    return s->avctx->global_quality == 0;
763
+#endif
764
+}
765
+
766
+static const double color15_7_factor = 100;
767
+
768
+static int optimum_dist(FlashSV2Context * s)
769
+{
770
+#ifndef FLASHSV2_DUMB
771
+    double ideal =
772
+        s->avctx->bit_rate * s->avctx->time_base.den *
773
+        s->avctx->ticks_per_frame;
774
+    int dist = pow((s->total_bits / ideal) * color15_7_factor, 3);
775
+    av_log(s->avctx, AV_LOG_DEBUG, "dist: %d\n", dist);
776
+    return dist;
777
+#else
778
+    return 15;
779
+#endif
780
+}
781
+
782
+
783
+static int reconfigure_at_keyframe(FlashSV2Context * s, const uint8_t * image,
784
+                                   int stride)
785
+{
786
+    int update_palette = 0;
787
+    int res;
788
+    s->block_width = optimum_block_width(s);
789
+    s->block_height = optimum_block_height(s);
790
+
791
+    s->rows = (s->image_height + s->block_height - 1) / s->block_height;
792
+    s->cols = (s->image_width +  s->block_width -  1) / s->block_width;
793
+
794
+    if (s->rows * s->cols != s->blocks_size / sizeof(Block)) {
795
+        if (s->rows * s->cols > s->blocks_size / sizeof(Block)) {
796
+            s->frame_blocks = av_realloc(s->frame_blocks, s->rows * s->cols * sizeof(Block));
797
+            s->key_blocks = av_realloc(s->key_blocks, s->cols * s->rows * sizeof(Block));
798
+            if (!s->frame_blocks || !s->key_blocks) {
799
+                av_log(s->avctx, AV_LOG_ERROR, "Memory allocation failed.\n");
800
+                return -1;
801
+            }
802
+            s->blocks_size = s->rows * s->cols * sizeof(Block);
803
+        }
804
+        init_blocks(s, s->frame_blocks, s->encbuffer, s->databuffer);
805
+        init_blocks(s, s->key_blocks, s->keybuffer, 0);
806
+
807
+    }
808
+
809
+    s->use15_7 = optimum_use15_7(s);
810
+    if (s->use15_7) {
811
+        if ((s->use_custom_palette && s->palette_type != 1) || update_palette) {
812
+            res = generate_optimum_palette(&s->palette, image, s->image_width, s->image_height, stride);
813
+            if (res)
814
+                return res;
815
+            s->palette_type = 1;
816
+            av_log(s->avctx, AV_LOG_DEBUG, "Generated optimum palette\n");
817
+        } else if (!s->use_custom_palette && s->palette_type != 0) {
818
+            res = generate_default_palette(&s->palette);
819
+            if (res)
820
+                return res;
821
+            s->palette_type = 0;
822
+            av_log(s->avctx, AV_LOG_DEBUG, "Generated default palette\n");
823
+        }
824
+    }
825
+
826
+
827
+    reset_stats(s);
828
+
829
+    return 0;
830
+}
831
+
832
+static int flashsv2_encode_frame(AVCodecContext * avctx, uint8_t * buf,
833
+                                 int buf_size, void *data)
834
+{
835
+    FlashSV2Context *const s = avctx->priv_data;
836
+    AVFrame *pict = data;
837
+    AVFrame *const p = &s->frame;
838
+    int res;
839
+    int keyframe = 0;
840
+
841
+    *p = *pict;
842
+
843
+    /* First frame needs to be a keyframe */
844
+    if (avctx->frame_number == 0)
845
+        keyframe = 1;
846
+
847
+    /* Check the placement of keyframes */
848
+    if (avctx->gop_size > 0) {
849
+        if (avctx->frame_number >= s->last_key_frame + avctx->gop_size)
850
+            keyframe = 1;
851
+    }
852
+
853
+    if (buf_size < s->frame_size) {
854
+        //Conservative upper bound check for compressed data
855
+        av_log(avctx, AV_LOG_ERROR, "buf_size %d <  %d\n", buf_size, s->frame_size);
856
+        return -1;
857
+    }
858
+
859
+    if (!keyframe
860
+        && avctx->frame_number > s->last_key_frame + avctx->keyint_min) {
861
+        recommend_keyframe(s, &keyframe);
862
+        if (keyframe)
863
+            av_log(avctx, AV_LOG_DEBUG, "Recommending key frame at frame %d\n", avctx->frame_number);
864
+    }
865
+
866
+    if (keyframe) {
867
+        res = reconfigure_at_keyframe(s, p->data[0], p->linesize[0]);
868
+        if (res)
869
+            return res;
870
+    }
871
+
872
+    if (s->use15_7)
873
+        s->dist = optimum_dist(s);
874
+
875
+    res = write_bitstream(s, p->data[0], p->linesize[0], buf, buf_size, keyframe);
876
+
877
+    if (keyframe) {
878
+        new_key_frame(s);
879
+        p->pict_type = FF_I_TYPE;
880
+        p->key_frame = 1;
881
+        s->last_key_frame = avctx->frame_number;
882
+        av_log(avctx, AV_LOG_DEBUG, "Inserting key frame at frame %d\n", avctx->frame_number);
883
+    } else {
884
+        p->pict_type = FF_P_TYPE;
885
+        p->key_frame = 0;
886
+    }
887
+
888
+    avctx->coded_frame = p;
889
+
890
+    return res;
891
+}
892
+
893
+static av_cold int flashsv2_encode_end(AVCodecContext * avctx)
894
+{
895
+    FlashSV2Context *s = avctx->priv_data;
896
+
897
+    cleanup(s);
898
+
899
+    return 0;
900
+}
901
+
902
+AVCodec ff_flashsv2_encoder = {
903
+    "flashsv2",
904
+    AVMEDIA_TYPE_VIDEO,
905
+    CODEC_ID_FLASHSV2,
906
+    sizeof(FlashSV2Context),
907
+    flashsv2_encode_init,
908
+    flashsv2_encode_frame,
909
+    flashsv2_encode_end,
910
+    .pix_fmts = (enum PixelFormat[]) {PIX_FMT_BGR24, PIX_FMT_NONE},
911
+    .long_name = NULL_IF_CONFIG_SMALL("Flash Screen Video Version 2"),
912
+};